A Dynamic Model Predicting Gestational Weight Gain. Diana M. Thomas, Ph.D. Montclair State University, Montclair, NJ

Transcription

1 A Dynamic Model Predicting Gestational Weight Gain Diana M. Thomas, Ph.D. Montclair State University, Montclair, NJ

2 Purpose Overview Clinical Utility Methods Validation

3 How much weight should I gain? Energy cost of Pregnancy = 85,000 kcal Additional EI of 300 kcal/d 3500 Calorie Rule Arrive at: ~25 lb weight gain Hytten FE, Leitch I (1971). The physiology of human pregnancy. Hytten FE, Chamberlain G. (1980) Clinical physiology in obstetrics

4 Institute of Medicine (IOM) recommends weight gain by pre-pregnancy BMI Purpose IOM and NRC, Weight Gain During Pregnancy ed. K.M. Rasmussen and A.L. Yaktine Washington D. C.: The National Academies Press.

5 Why manage gestational weight gain (GWG)? Purpose 60% Short of women term: of childbearing age classified overweight or obese. (High BMI) Increased Risk for GDM, Preeclampsia (High GWG) C-section. (2009 Pregnancy Surveillance System) Over 55% of Long overweight term: and obese women gain more than the 2009 (High recommended BMI and GWG) guidelines. Postpartum weight retention, Increased maternal body fatness and risk factors for cardiovascular disease DHHS and CDC, Pregnancy Nutrition Surveillance 2009 Report Beyerlein, A., N. et al., Within-population average ranges compared with Institute of Medicine recommendations for gestational weight gain. Obstetrics and gynecology, Fraser A, Tilling K, Macdonald-Wallis C, et al. Associations of gestational weight gain with maternal body mass index, waist circumference, and blood pressure measured 16 y after pregnancy: Am J Clin Large for gestational age infants Nutr 2011; 93:

6 How does a mathematical model help? Purpose 1. Enables setting precise goals with a health care provider. 2. Provides Continuous Feedback 3. Generates Opportunities to Intervene and Manage Weight Gain Schultz, W., Behavioral theories and the neurophysiology of reward. Ann Rev Psychol, : p

7 Purpose Overview Clinical Utility Methods Validation

8 Java Based System to Manage GWG Clinical Utility User enters baseline data: Age Height Pre-gravid Weight Adjusts EI by trimester Weight Gestational Week

9 Java Based System to Manage GWG Clinical Utility Green Zone IOM recommended range

10 Java Based System to Manage GWG Clinical Utility Blue Curve Model predicted weight Outside Recommendations

11 Java Based System to Manage GWG Clinical Utility Adjust EI Blue Curve Model predicted weight Inside Recommendations

12 Model can be applied to determine additional EI by trimester Clinical Utility Classification Pre-gravid weight (kg) Pre-gravid BMI (kg/m 2 ) Target GWG (kg) Trimester Model predicted ΔEI (kcal/d) Trimester Underweight Normal Overweight Obese

13 Model can be used to compare different recommendations Clinical Utility IOM Weight Range GWG resulting from FAO/WHO/UNU United Nations University World Health Organization Food and Agriculture Organization of the United Nations, Human energy requirements. Report of a Joint FAO/WHO/UNU Expert Consultation, Rome, October 2001.

14 Purpose Overview Clinical Utility Methods Validation

15 There are pregnancy specific challenges for model development Methods Pre-Gravid Weight Body Composition Measurements Components of Energy Expenditure (RMR, TEF,SPA,PA)

16 The Butte study contains the necessary measurements for model development Methods Simultaneous measurements at weeks 0, 9, 22, 36 Body composition (body weight, TBW, body volume, bone mineral content) Energy expenditures (DLW) RMR (respiration calorimetry) Butte NF et al. Energy requirements during pregnancy based on total energy expenditure and energy deposition. Am J Clin Nutr

17 The first mathematical model that predicts weight gain during pregnancy Methods

18 Purpose Overview Clinical Utility Methods Validation

19 The model agrees with observed data from the Kopp- Hoolihan Study Validation FFM TBW FM Kopp-Hoolihan LE, et. Al., Longitudinal assessment of energy balance in well-nourished, pregnant women. Am J Clin Nutr Apr;69(4):

20 Model predictions agree with observed data from the Goldberg study Validation FFM TBW FM Goldberg GR, Prentice AM, Coward WA, Davies HL, Murgatroyd PR, Wensing C, Black AE, Harding M, Sawyer M. Longitudinal assessment of energy expenditure in pregnancy by the doubly labeled water method., Am J Clin Nutr Apr;57(4):

21 Thank you to my Collaborators Jesus E. Navarro-Barrientos Daniel E. Rivera Steven B. Heymsfield Carl Bredlau Leanne M. Redman Corby K. Martin Sally Lederman Kelly Orzechowski Richard C. Miller Linda Collins Nancy Butte

22 Questions?